From d289232e21bb9d2b63d5ab93c1975b18adb4be3a Mon Sep 17 00:00:00 2001 From: Jack Kinsey Date: Tue, 3 Dec 2019 22:10:49 -0500 Subject: [PATCH] Add correct day3pt1 --- src/adventofcode2019/day03.clj | 50 ++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 src/adventofcode2019/day03.clj diff --git a/src/adventofcode2019/day03.clj b/src/adventofcode2019/day03.clj new file mode 100644 index 0000000..17564de --- /dev/null +++ b/src/adventofcode2019/day03.clj @@ -0,0 +1,50 @@ +(ns adventofcode2019.day03 + [:require [adventofcode2019.lib :refer :all] + [clojure.string :as str] + [clojure.set :as set] + [clojure.math.combinatorics :as combo]]) + +(defn parse-input [input] + (map #(str/split % #",") (str/split-lines (str/trim (slurp input))))) + +(defn spec->op [spec] + (let [direction (first spec) + distance (parse-int (str/join (rest spec)))] + (case direction + \U (fn [[x y]] [x (+ y distance)]) + \D (fn [[x y]] [x (- y distance)]) + \R (fn [[x y]] [(+ x distance) y]) + \L (fn [[x y]] [(- x distance) y])))) + + +(defn ints-between [x y] + (cond + (> x y) (range y (inc x)) + (< x y) (range x (inc y)) + :else [x])) + +(defn points-diff [pos-a pos-b] + (let [[a-x a-y] pos-a + [b-x b-y] pos-b] + (set (for [x (ints-between a-x b-x) + y (ints-between a-y b-y)] + [x y])))) + +(defn wire-spec->points [wire] + (let [wire-ops (map spec->op wire) + trace-reduction (fn [{:keys [pos points]} op] + (let [new-pos (op pos) + new-points (points-diff pos new-pos)] + {:pos new-pos :points (set/union points new-points)})) + trace (reduce trace-reduction {:pos [0 0], :points #{}} wire-ops)] + (:points trace))) + +(defn find-intersections [wires] + (let [wires-points (map wire-spec->points wires)] + (set/difference (apply set/intersection wires-points) #{[0 0]}))) + +(defn day03 [] + (let [wires (parse-input (input-file)) + manhattan-distance (fn [[x y]] (+ (Math/abs x) (Math/abs y))) + intersections (find-intersections wires)] + (println (apply min (map manhattan-distance intersections))))) -- 2.38.5